Added certificate file and referenced it in the corresponding test. Patched MetaDataMDX to avoid same issue there

Author: Bogdan Despotov

src/saml2/mdstore.py

@@ -814,7 +814,7 @@ def __getitem__(self, item):
             response = requests.get(mdx_url, headers={
                 'Accept': SAML_METADATA_CONTENT_TYPE})
             if response.status_code == 200:
-                _txt = response.text.encode("utf-8")
+                _txt = response.content
 
                 if self.parse_and_check_signature(_txt):
                     return self.entity[item]

tests/SWITCHaaiRootCA.crt.pem

@@ -0,0 +1,22 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/test_30_mdstore.py

@@ -390,7 +390,7 @@ def test_load_remote_encoding():
     crypto = sigver._get_xmlsec_cryptobackend()
     sc = sigver.SecurityContext(crypto, key_type="", cert_type="")
     httpc = HTTPBase()
-    mds = MetaDataExtern(ATTRCONV, 'http://metadata.aai.switch.ch/metadata.aaitest.xml', sc, '/tmp/SWITCHaaiRootCA.crt.pem', httpc)
+    mds = MetaDataExtern(ATTRCONV, 'http://metadata.aai.switch.ch/metadata.aaitest.xml', sc, full_path('SWITCHaaiRootCA.crt.pem'), httpc)
     mds.load()